A powerpoint highlighting the natural and human causes of climate change

1. The Causes of
Global Climate Change

2. How has the global temperature fluctuated in the past?
What were the causes of these changes?

4. Describe the pattern of climate change shown above

5. Climate Forcing: Any mechanism that alters
the global energy balance and ‘forces’ the
climate to change in response.

6. What are the Natural Causes of
Climate Change?

7. 1. Solar Output
Describe the pattern of solar output from 1800 to 2000.
What are the two main patterns that you see?

8. 2. Volcanic Eruptions
What effect do volcanic eruptions
have on global climate?
Use the diagram on the right to
explain the effect of volcanic
eruptions on the climate

9. 3. The Milankovitch Cycles
Why would the surface temperature of the earth change if the tilt of the earth or orbit
changes?

10. There is overwhelming evidence to suggest that our current
climate is different from that of previous human experience:
The level of Co2 in the atmosphere is far above the
“natural” level and continues to rise
11 of the 12 warmest years on record occurred between
1995 and 2006
1950 to 2000 was the warmest 50 year period for 1300
years
Temperature rises have been recorded on all continents
since 1970
Satellite observations since 1993 suggest an annual rise in
sea level of 3.1 mm
Extreme weather events are increasing

11. So shouldn’t we just blame only natural
causes for the warming that we are
experiencing today?

12. The observed widespread warming of the
atmosphere and ocean, together with ice mass
loss, support the conclusion that it is extremely
unlikely [<5% chance] that global climate change
of the past 50 years can be explained without
external forcing and very likely that it is not due
to known natural causes alone. During this
period, the sum of solar and volcanic forcings
would likely [>66% chance] have produced
cooling, not warming.
IPCC 4TH Assessment 2007

13. What are the Human Causes of
Climate Change?

16. Suggest the causes of the sudden increase in green house gases after the 1800’s?
What are the sources of greenhouse gases?

18. Where previously, temperature rise has caused a rise in Co2, in the modern era, it is
Co2 which is preeceeding the temperature increase.

19. http://mabhobs.org/de/content/global-temperature-world-population-co2-concentration-graph-1880-2008

20. Go www.thegeographer.co.uk/videos
Click on 11th Hour and make full screen.
Select the section from 12- 28min
Watch and make notes.